TO-DO LIST

QUESTIONS

LINKS

https://www.youtube.com/c/ifilmthis/videos

  1. Why is Scenario 1 an intrinsic pathway while Scenario 2 is an extrinsic pathway?

    1. Extrinsic pathway occurs when the environment or there are external signals that determine that a cell must die. Therefore, isn't Scenario 1, where there is a lack of oxygen, an extrinsic pathway?
    2. Similarly, an intrinsic pathway occurs when there is injury in the cell or there are intracellular signals. Therefore, isn't Scenario 2 an intrinsic pathway? I understand that the question did mention Fas-ligand therefore it is an extrinsic pathway, but I do not understand how external signals are involved in this Scenario for it to be an extrinsic pathway.

    Teacher's explanation: (to get the red colour, just press the slash key and type the colour you want)

    I have no idea from where you learned that external signal for extrinsic pathway and internal signal for intrinsic pathway in which the concept is totally wrong.

    Below the diagram indicates the extrinsic pathway with induced by a ligand (Fas) from another cell (lymphocyte or T cell). When Fas ligand binds to the Fas ligand-receptor of a cell, the binding itself will trigger an extrinsic apoptotic pathway in the cell. This is commonly happening when immune cells bind to their targets for eliminating harmful cells in the body. Extrinsic apoptosis also plays a role in the selection of the right type of T cells to be released into blood circulation for effective immunity.

    https://mail.google.com/mail/u/3?ui=2&ik=9f8ad13367&attid=0.1&permmsgid=msg-f:1700982114077053239&th=179b1a3876db1137&view=fimg&sz=s0-l75-ft&attbid=ANGjdJ992KrpJm4LPHo6AxC7ESDCY3R9kmnaBzA_q77-mjrtk_XAWK8mHRUzWAVmyXYVyyHzXjS3HqOy-OkpsuLG6uDlmDqWMt2ZRjaWmGP_hRkHMeXOnJ02UEU5byo&disp=emb&realattid=ii_kp7x0cnm0

    Scenario 2 in the workshop is describing a situation where autoreactive T cells failed to be removed by extrinsic apoptosis. Autoreactive T cells are dangerous because they will kill other T cells which are supposed to target other cells (not their own type) to achieve effective immunity. When extrinsic apoptosis failed to occur in T cells for removal of autoreactive T cells, the T cells will move around in the blood circulation and massively kill other T cells, which is one of the conditions that contribute to the autoimmune response in the body.

    Answers to the question set for Scenario 2: Fas ligands do not bind the Fas receptor and DISC is not formed are both describing a failed extrinsic apoptosis. Eventually, the survived autoreactive T cells keep proliferating, then massively kill other T cells, subsequently lead to an autoimmune disorder.

  2. In one of the slides/questions, it was asked 'What apoptotic event or series of events could have led to the autoimmune response?"

    1. I do not understand answer C where "DISC is not formed". How does the lack of DISC induce an autoimmune response?

    CONCISE NOTES

    1. Subtopic

      1. important points
        1. examples/explanations/additional information

    2. 2 ways cells can die

      1. Apoptosis
        1. genetically programmed cell death
      2. Necrosis
        1. unforeseen factors > leads to uncontrollable cell death > damages surrounding tissue
          1. cuz cellular contents inside the cell leaks out
          2. preinflammatory cytokines come in > creates inflammation > damages surrounding cells